In oil and gas drilling, wellbore stimulation is a common treatment performed in subterranean formations to enhance or restore the productivity of oil and gas from a wellbore. Acid treatments, as detailed infra, may be used for wellbore stimulation. Acidizing is a stimulation acid treatment technique in which a treatment fluid comprising aqueous acid solution is delivered into the subterranean formation to dissolve acid-soluble materials, such as carbonates. In a functioning wellbore, channels in the surrounding formation carry gas and oil from the formation to the wellbore. Carbonate formations can block or obstruct these channels. Acidic solutions may be utilized to acidize the carbonate formations and improve the productivity of the wellbore. These carbonate formations may impact the productivity of a wellbore. This can increase the permeability of a treatment zone and enhance well production by increasing the effective wellbore radius.
Standard hydrochloric acid reacts very quickly in carbonate formations. The reaction is so rapid in high temperatures that it is impossible for acid to penetrate, or wormhole, more than a few inches into the formation. In such cases, the acid is rendered ineffective in stimulating the wellbore.